I wanted to share my experience with a couple of performance mods. I have a 2008 WRR with stock gearing. Modes are Q4 exhaust, pc v with a map I downloaded from here. I have also opened up the airbox with 1/2" holes in the airbox door.
From my Butt Dyno, I feel like the bike rev's quicker and feels like it has more power. Other changes I have noticed; I can now hit rev limiter in the 3rd and 4th gear. The biggest difference is that 6th gear is actually usable. My opinion is that 6th gear feels like it has the pull of 5th gear without the mods.
Now for the data. According to Cycle World, 0-60 for the WRR is 6.7 seconds. Using my iPhone with CT Speedometer Lite I made a couple of passes using the 0-60 timer. The best run was 4.3 and the worst was 6.0 seconds. The 4.3 second run felt the best, I thought I was good on my shifts and hit the rev limiter in 3rd just after 60. The 6.0 second run didnt feel good, I hit the rev limited in 1st and 2nd, and shifted into 4th too early.
Just my experience, and one more data point to consider when thinking about changes